Poison ivy, Toxicodendron radicans, is a native perennial of the cashew family that grows throughout eastern North America, including most West Virginia counties, and appears in many forms, from a small herb or shrub to a trailing vine or a thick, hairy vine climbing high into trees. It prefers moist, fertile, well-drained soil but also grows in acid to somewhat alkaline soils, rocky dry places, and saturated seeps, tolerates drought, flooding, and cold, reaches all elevations in Appalachia up to about 3500 feet, and is commonly found along the edges of paths, ponds, streams, fields, and yards. Male and female flowers grow on separate plants, so only female plants produce clusters of whitish drupes, and the plant is identified by bright green trifoliate leaves with smooth or toothed edges that turn bright to deep red in fall, sometimes with black spotting. Its toxicity comes from urushiol, an oily chemical released when roots, stems, or leaves are damaged; in sensitive people it combines with skin proteins and triggers an immune response that usually causes itchy contact dermatitis and watery blisters. Urushiol can be removed soon after exposure by vigorous washing with a strong, degreasing detergent, blister fluid does not spread the rash, but the chemical can be transferred from clothing or pets, and if the plant is burned it can enter the smoke and cause serious irritation to the eyes, throat, and lungs. Though troublesome for humans, poison ivy is browsed by deer, its fruits feed game birds, song birds, and small mammals, it is often confused with Virginia creeper and box elder, and it had limited ethnobotanical use, including as a tonic by the Houma Indians of Louisiana and as an emetic by the Cherokee.